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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
I could be wrong, but I thought the whole "D" vs "Round" port thing has been proven that neither has any benefit over the other. Now as to header design, fitment, power, etc...I'm interested to hear real conclusive data...however that may be captured. I'm guessing they're extremely similar from a sheer numbers standpoint.
Im also considering SW Headers in their 2" version. There is a local Z making a bit over 640RW with stock shortblock, Holley High-Ram that runs this header. She is a beast.
On a 2" header the flange port is bigger than the head anyway so it doesn't matter. ARH headers are on more record breaking LS cars than any other header, gm also uses them on its copo program. Iirc ARH used to use d ports on their 2" flanges but later found they served no value
On a personal note I have installed Kooks and ARH 2" headers....this is not going to be a popular opinion but the kooks quite honestly sucked compared to ARH in terms of install and fitment
Im also considering SW Headers in their 2" version. There is a local Z making a bit over 640RW with stock shortblock, Holley High-Ram that runs this header. She is a beast.
I have installed all three major brands of corvette headers.
Fitment from best to worst:
ARH
KOOKS
LG
Construction quality best to worst
ARH
LG
KOOKS
ARH is hands down the superior header, we are lucky to have them for the vette. The 2" ARHs I just installed on my personal car tuck beautifully around the engine bay and ZR1 oil cooler. Amazing really.
The thread is about 2" headers. You tried calling me out for being incorrect, I let you know that you stand corrected, and you tell me I should "specify" 2" in a 2" thread? You were mistaken in the context of this thread, you throw out "not true" accusations, but you are above admitting when you're wrong? I'll keep that in mind when I read your comments from now on. It's about sharing knowledge.
I'm not in error. Kooks offers 2 different collectors for their 2" primary LS7 Z06 header, straight and merged. I won't belabor this any more and post links. This is your thread and I'm out. Let me know though and I can PM you the links should you decide.
I've installed 4 sets of kooks on various cars and 3 sets of ARH....kooks quality has never impressed me for the money and the fitment on all cars was less than optimal. ARH on the other hand has always went right in with plenty of clearance
Had kooks 2" on my Z06 and was not impressed for the money. Installing them was a b!tch on the pass side. Once in they werent bad. I didnt like the X-pipe either. I had to use a ratchet strap to install them. I will be trying the SW 2" headers on my new car though, I have seen the quality of those headers and it is way up there and $400 cheaper. Now as the "D" vs "O" port, as long as there is no interference in the flow, there will be no gain or loss. Now if there is an interference there will be a loss due to a reverence in exhaust gasses causing knock. My particular heads, the "D" port caused an interference and this is what I saw. So I installed the 2" Kooks w/ no cats and saw an increase of 45 RWHP over the stock manifolds. This is just my personal experience.
03-09-2017, 11:10 AM
Feedback on Kooks 2" vs ARH 2"
